Cylinder grinder



June 25, 1968 J. M. SUDDARTH ET AL 3,389,508

CYLINDER GRINDER Filed July 1, 1964 a Sheets-Sheet 1 i 322.. I 6 l J lllfllllll mvmvrons JACK M. SUDDARTH D L. GRAY AgRNEY June 25, 1968 J- M.SUDDARTH ET AL 3,389,508

CYLINDER GR INDER Filed July 1, 1964 5 Sheets-Sheet 2 June 25, 1968 M.S'UDDARTH ET AL 3,389,508

CYLINDER GRINDER Filed July 1, 1964 3 Sheets-Sheet 5 H2) ro 990- v IREG. 7 A

' \o-2o PSI Am T PRESSURE o a *3 SOURCE G "6 United States Patent a6,389,508 i CYLINDER GRINDER JackM. .Suddarth, Fort Gibson, and Dolph L.Gray,

v Muskogee, Okla, assignors to Coburn Manufacturing Company, Inc.,Muskogee, 0kla., a corporation of Oklahoma Filed July 1, 1964, Ser. No.379,509

r 7 Claims. (CI. 51-60) This invention pertains generally toimprovements in lens grinding'and polishing machines and, moreparticularly, relates toimprovement's in machines for polishing andlining the surfaces of cylindrical lens blanks. Machines of this typeare comprised generally of a cylinder lap supportedon a platform inwhich there is introduced an irregular movement referred to in the artas a breakup movement, together with means for maintaining the lens inengagement with the moving lap. The prior art is well aware ofmechanisms for producing break-up movements. 'For instance, the UnitedStates patent to Long, No. 2,159,620, and the United States patent toLockhart, No. 2,168,843, disclose structures that are illustrative ofthis movement. In the invention described herein, the lens blanksupporting structure receives an orbiting movement over the break-upmovement of the lens lap. The above movements result in a variation ofmovement over the lap surface for the purpose of preventing theformation of aberrations, waves and distortions in the surface of thelens which will occur if the polishing process is not performed over theentire lap surface. i t

"A principal objective of this invention is to provide an automatic,pneumatic pressure mechanism providing a first pressure at the start ofthe finishing process and after a certain selected time, substantiallyincreasing said start pressure. The result obtained from this processeliminates the serious breakage problem which often occurs in thepolishing ofcylinder lenses.

The lens blank under discussion is secured at the lower end of anassembly which lifts and lowers the lens blank drive mechanism into andout of engagement with the lens back of the lens to be ground. Thisassembly can be termed as a head. The head, as it transmits its orbitingmovement to the lens, receives both lateral and longitudinal stresses.It is an important objective of this invention to provide a supportinghead of simple and durable construction for efiiciently assuming thesestresses.

Another important objective of this invention is to p'rovide a mechanismfor raising and lowering the head into and out of engagement with thelens blank in a manner whereby when the head is lowered to the properposition, it is automatically secured and will not retract except foradirect releasing movement by an operator.

A still further objective of this invention is to provide amachine ofthe type described wherein breakage is lessened by having a series offluid pressures applied under the control of timing valves whereinpolishing is begun at a reduced pressure and after a selected amount oftime, increased pressure is automatically placed on the lens. Thispermits an operator to attend other equipment during thepolishingoperation. In the prior art it was often necessary to have anoperator remain at the machine for submitting the lens to increasingpressures as the polishing operation proceeded.

These and other objectives and advantages of the invention will be morefully understood upon a reading of the following specification taken inview of the attached drawings whereinr V FIGURE 1 is a diagrammatic(somewhat exaggerated) view of the lens and lap prior to polishing;

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[FIGURE 2 is a'front perspective view of the machine with portionsbroken away;

FIGURE 3 is an exploded perspective of the supporting head assembly andthe handle lock assembly;

FIGURE 4 is an assembled side elevation of the handle lock assembly; 7

FIGURE 5 is a cross-sectional view of the handle lock assembly along theline 55 of FIGURE 4;

FIGURE 6 is a view similar to FIGURE 5 with the elements moved to theirlocking position;

FIGURE 7 is an assembled view of the supporting head assembly of FIGURE3; and

FIGURE 8 is a schematic of the fluid pressure and timing valveapparatus. 7

Referring now to the drawings wherein a preferred embodiment of theinvention is disclosed, like numerals are used to indicate like elementsin the several views. The numeral 10 indicates generally the housing ofa lens polishing machine. Attached to the front of the housing is apolishing bowl 12. The bowl is suitably equipped with means to provide agrinding slurry to the polishing area but these particular means form nopart of the present invention.

The actual polishing and finishing of the lens takes place within thebowl 12. Disposed Within the bowl are a pair of lap supports '13 and 13ato which a pair of laps L are mounted. A brief referral to FIGURE 1 willdisclose that prior to finishing a lens blank B, only the edge portionsof the blank engage .the cylinder lap. When a downward pressure isexerted on the blank, lines of stress develop generally long the arrows1 5. This invention is directed primarily to a means for automaticallymaintaining the pressures at a reduced level until the lines of stressare dispersed due to an initial removal of glass from the edges of theblank.

A break-up motion of the type heretofore described is imparted to themembers 13 and 13a via the shafts 14 and 14a. At their outer ends theshafts are provided with handles and diaphragms for sealing the bowlapertures through which they extend. This last-mentioned arrangementfacilitates removing the bowl when desired. It should be understood thatthe break-up movement occurs in a common plane without any rotationalmovement being transmitted to the laps.

Extending upwardly and somewhat forwardly of the housing 10 are a pairof standards 16 and 16a. Since the apparatus supported by standard 16and all structure associated therewith is identical to that supported by16a, only the standard 16 will be discussed in any detail. At itsuppermost end, the standard 16 is horizontally journaled at 18 toreceive the handle locking assembly 19 which is described in detailhereinafter. Forward of the journal is a bracket 20 having a verticalslideway 21 therethrough.

lidably received within the way 21 is the upper end of a lens blanksupporting and driving assembly 26.

The drive assembly is supported by a rack 28 which is slidably receivedin slideway 21. The rack 28 is raised and lowered within the way via apinion 30 which is operably connected to the handle lock assembly 19.The rack and pinion are utilized to raise and. lower the drive headassembly with respect to the lap L. A suitable opening between thejournal 18 and the slideway 21 permits the pinion to mesh with the rack.

The handle assembly 19 is elfective to maintain the rack 28 at a fixedheight regardless of longitudinal forces acting longitudinally upwardlythereof. In this respect, the handle assembly is a one-way clutch. Thehandle look assembly includes a shaft 34, the inner end of whichsupports the pinion 30 and the outer end of which is rotatably receivedin a bushing 35. Fixedly secured intermediate the rod end is afour-sided cam 36. The cam is receivable in a cylinder-like member 38which extends inwardly of bushing 35. The interior diameter of member 38is only slightly greater than the diagonal length of cam 36.

The cylinder 38 is formed with a plurality of slots 39. A plastic body44 encompasses the cylinder and forms with the cam 36 and slots 39 aseries of chord-like chambers 40, each of which houses a pin 42. Thebody 44 is provided with an outer flange 45 which is secured to standard16 by screws or the like.

An understanding of the handle lock assembly can best be had byreferring to FIGURES 4, and 6. As previously described, the member 44 isfixed to the standard, and the shaft 34, cam 36 and pinion rotate as aunit. The outer end of shaft 34 is rotatably secured in the handle unitconsisting of cylinder 44, bushing 35, and handle 37. Therefore, as thecylinder 44 is rotated counterclockwise (clockwise as viewed in FIGS. 5and 6) under the influence of the handle 37, the rack 28 is loweredtoward the lens and lap.

Prior to the rotational movement in handle 37 acting on pinion 30, acertain amount of free-play occurs between the cylinder 44 and the cam36. For purposes of description, the location of elements as viewed inFIG- URE 5 can be termed a neutral position. As the cylinder 38 isrotated, the pins 42 receive a lateral or circumferential force alongarrow F wedging them into the narrow portion of their respective chordalchambers 40, as seen in FIGURE 6. When resistance is met and the pinsbind between the sides ofcam 36 and the interior of member 44, the shaft30 will then rotate with the handle whereby the head asembly is lowered.

Thereafter, forces attempting to lift rack 28 will transmit a rotationalforce in shaft 34 which acts generally along the force lines 43 ofFIGURE 6. Such forces are dissipated in further compressing the pinsrather than ro tating the cylinder. When it is desired to lift the rack,the handle 37 is moved in the opposite direction, creatingcircumferential forces 47 which readily dislodge the pins. The rackbegins an upward movement when the pins bind at the opposite narrowportions of chambers 40.

As previously mentioned, the rack 28 supports the drive assembly 26. Thelowermost end of the rack is formed with a pocket which receives theupper end of stub shaft 48. The shaft is fixedly secured to the pocketby set screws or the like. A joint 49 consisting of three brackets isformed between the rack and the assembly 26. The lower end of the shaftis formed with a bracket member 50. Downwardly depending from each endof the bracket are a set of conical bearings 52 and 54. Disposedimmediately below the bracket is second bracket 56 having sockets 58 and59 for respectively receiving the bearings 52 and 54. A pair of arms 60and 62 extend outwardly and upwardly from the midportion of bracket 56as best seen in FIGURE 3. Depending downwardly from the outer ends ofarms 60 and 62 is a second set of conical bearings 64 and 66 which arereceivable respectively in sockets 68 and 69 of a third bracket 70. Thebracket 70 is provided with an opening 72 to removably receive the upperend of a lower shaft 74. The bracket 70 is tightened about the shaft 74via a bolt 75. The brackets 50, 56 and 70 form a suspension joint 71 forpurposes described hereinafter. The brackets are held in engagement withone another by an endless resilient band 73 having one end looped underone end of bracket 70 across the upper surface of bracket 50 and belowthe end of arm 70.

The lower end of shaft 74 forms the upper end of a pneumatic cylinder76. Slidably received in cylinder 76 is a piston 78 having a piston rod80 extending downwardly through the other end of the cylinder. Fixedlysecured to the bottom of rod 80 is a yoke 82. The yoke carries a rocker84 which is pivotally suspended therefrom by linkage arms 88 and 90. Therocker carries a transverse crossbar 92 having pins 94 which are adaptedfor driving engagement with the conventional recesses of the lens blockB.

Intermediate the length of rod is a circular sheavelike member 95. Asseen best in FIGURE 7, the rod is offset from the center of the sheavean amount D for causing the rod to travel a circular path as the sheaveis rotated. A strap 98 engages the sheave 96 and also engages apparatusin housing 10 for transmitting the continuous orbital or circularmovement to the head. The orbital movement, of course, must be limitedin diameter so that the lens will always be within the periphery definedby the break-up movement.

The expansion chamber 99 of the cylinder 76 is pressurized via a sourceof pressurized air 100. A schematic of the pneumatic and timing valvesis shown in FIGURE 8. The source of pressurized air is divided into twobranches by conduits 102 and 104. Across conduit 102 is laced a pressureregulator 106 and across conduit 104 is placed a pressure regulator 108.The regulators are of an adjustable type and desirably the regulator 106is set at approximately 10-20 p.s.i. and regulator 108 at from 70-90p.s.i.

A timing apparatus 110 of a conventional re-set type is connected tooperate the solonized air valves 112 and 114 which are respectivelyplaced across conduits 102 and 104. For the first several minutes ofoperation, the timer is set to open the valve 112 to permit the lowerregulated pressure in line 102 to be communicated to line 116 andchamber 99 and, thereafter, close valve 112 and open line 116 andchamber 99 to the higher pressure by opening valve 114. A pressureindicator dial 118 is placed across conduit 116 for informative reasons.

In operation, an attendant first places a lap of the desired cylindricalconfiguration on the supports 13 and 13a. Thereafter, a blocked lensblank B is centrally placed over the lap. While holding the lens inposition with one hand, the attendant grasps handle 37 with the other tolower the head assembly 26 until pins 94 engage the appropriate recessesformed in the rear of the lens block. As has previously been described,insofar as movement longitudinal of member 28 is concerned, only thatmovement transmitted through handle 37 can now affect the raising orlowering of the upper portion of the head assembly.

Upon turning the timer to its start position, pressure is applied intochamber 99 via the low pressure regulator 106 and conduit 102. Oncechamber 99 is pressurized, the force maintaining the lens intoengagement with the lap is solely determined by the pressure. regulatorsand not handle 37. As has been previously mentioned, the initial lowpressure is regulated by member 106 and is maintained on the lens for aperiod of approximately five minutes. Thereafter, the timerautomatically communicates the higher pressure regulated by regulator108 to chamber 99 until final polishing is accomplished. During theperiod that pressure is applied and the lap support members arereceiving the break-up movement, the head 26 is orbited due to therotation of sheave 95.

The importance of the joint 49 can now be readily understood. As thehead is orbited, but not rotated since rod 80 is not fixed rotationallywith sheave 95, the rack 28 stays stationary and the rest of the headassembly is pivotal at joint 45. The pivoting movement occurs in a plane120 which intersects each of the pivot points at pins 64, 66, 52 and 54.In other words, a four point suspension in a common plane is availablewhich is readily disconnected by removing the resilient band 73. Thejoint is of a type uniquely adapted to take the longitudinal thrustswhich are transmitted by the pressure apparatus and the radial thrustswhich are transmitted by the orbiting apparatus.

In a general manner, while there has been disclosed an effective andefiicient embodiment of the invention, it should be well understood thatthe invention is not limited to such an embodiment, as there might bechanges made in the arrangement, disposition, and form of the partswithout departing from the principle of the present invention ascomprehended within the scope of the accompanying claims.

We claim:

1. A lens surfacing machine of the type having an abrading lap receivingirregular movements in a common plane and a lens blank supportingstructure for maintaining the blank in engagement with the lap, theimprovement in said structure comprising a framework forming a part ofthe machine, a supporting head assembly disposed above said lap andhaving an uppermost end slidably received in said framework, a cradle atthe lower end of said assembly, means to lower said assembly until saidcradle engages said blank, pneumatic means for maintaining a desiredpressure on said cradle, a resilient universal joint intermediate theends of said assembly between said cradle and that portion of saidframework slidably receiving said shaft.

2. A lens surfacing machine of the type having an abrading lap havingirregular movements in a common plane and a lens blank supportingstructure for maintaining the blank in engagement with the lap, theimprovement in said structure comprising, a framework forming a part ofthe machine, a supporting head assembly disposed above said lap, saidassembly comprising a first member slidably disposed with respect tosaid framework for movement toward and away from said lap, a lockingmechanism mounted on said framework for holding a portion of said firstmember at a selected position with respect to said lap, a pneumaticcylinder attached to one end of said first member, a drive member havingone end forming an expansion chamber with said cylinder and a second endfor engagement with said blocked lens, a pivotal joint intermediate thelength of said first memher and between said portion and said pneumaticcylinder, at first source of relatively high air pressure, a secondsource of relatively low air pressure, a conduit network forcommunicating said first and second sources to said chamber, timecontrolled valve means across said network for communicating said highpressure source to said chamber a selected period of time after said lowpressure source has been communicated thereto.

3. A lens surfacing machine of a type having an abrading lap havingirregular movements in a common plane and a lens blank supportingstructure for maintaining the blank in engagement with the lap, theimprovement in said structure comprising, a framework forming a part ofthe machine, a supporting head assembly disposed above said lap, saidassembly comprising a first member slidably disposed with respect tosaid framework for movement toward and away from said lap, a pneumaticcylinder attached to one end of said first member, a drive member havingone end forming an expansion chamber with said cylinder and a second endfor engagement with Cir said blocked lens, means driving said drivemember about a circular path over said lap, a first source of relativelyhigh air pressure, a second source of relatively low air pressure, aconduit network for communicating said first and second sources to saidchamber, time controlled valve means across said network forcommunicating said high pressure source to said chamber a selectedperiod of time after said low pressure source has been communicatedthereto.

4. A lens surfacing machine of the type having an abrading lap havingirregular movements in a common plane and a lens blank supportingstructure for maintaining the blank in engagement with the lap, theimprovement in said structure comprising, a framework forming a part ofthe machine, a supporting head assembly disposed above said lap, saidassembly comprising a first member slidably disposed with respect tosaid framework for movement toward and away from said lap, a pneumaticcylinder attached to one end of said first member, a resilient jointbetween said first member and said cylinder, a drive member having oneend forming an expansion chamber with said cylinder and a second end forengagement with said blocked lens, means driving said drive member abouta circular path, and a source of pneumatic pressure communicated to saidcylinder for urging said drive member toward said lap.

5. The machine of claim 1 wherein said assembly includes a verticallydisposed cylindrical middle portion, a shaft means enclosing the upperend of said cylindrical portion and extending upwardly therefrom, apiston rod having its upper end slidably disposed in the lower end ofsaid middle cylindrical portion and forming an expansion chamber withsaid shaft means and means communicating said expansion chamber withsaid pneumatic means.

6. The invention of claim 5 wherein said resilient universal joint isdisposed intermediate the ends of said shaft means.

7. The invention of claim 5 wherein said resilient universal joint isintermediate the ends of said shaft means between said uppermost end andsaid cylindrical middle portion.

References Cited UNITED STATES PATENTS 766,482 8/1904 Wolfe 51---l241,230,530 6/1917 Stead 51133 2,159,620 5/1939 Long 51---160 2,624,9811/1953 Kenyon 51-56 X 2,880,555 4/ 1959 Brueckner 51124 X 2,977,7244/1961 Kennedy 51-124 3,172,240 3/1965 Giardini 51-165 X HAROLD D.WHITEHEAD, Primary Examiner.

1. A LENS SURFACING MACHINE OF THE TYPE HAVING AN ABRADING LAP RECEIVING IRREGULAR MOVEMENTS IN A COMMON PLANE AND A LENS BLANK SUPPORTING STRUCTURE FOR MAINTAINING THE BLANK IN ENGAGEMENT WITH THE LAP, THE IMPROVEMENT IN SAID STRUCTURE COMPRISING A FRAMEWORK FORMING A PART OF THE MACHINE, A SUPPORTING HEAD ASSEMBLY DISPOSED ABOVE SAID LAP AND HAVING AN UPPERMOST END SLIDABLY RECEIVED IN SAID FRAMEWORK, A CRADLE AT THE LOWER END OF SAID ASSEMBLY, MEANS TO LOWER SAID ASSEMBLY UNTIL SAID CRADLE ENGAGES SAID BLANK, PNEUMATIC MEANS FOR MAINTAINING A DESIRED PRESSURE ON SAID CRADLE, A RESILIENT UNIVERSAL JOINT INTERMEDIATE THE ENDS OF SAID ASSEMBLY BETWEEN SAID CRADLE AND THAT PORTION OF SAID FRAMEWORK SLIDABLY RECEIVING SAID SHAFT. 